#include <stdio.h>

int main() {
  char str[101];
  int i, sum;
  printf("please input your S19string: ");
  gets(str);
  i = sum = 0;
  while (str[i] != 0) {
    sum += str[i++];
  }
  printf("sum res = %x\n", sum & (0x0FF));
  return 0;
}
